OK, I give up - need help

[Michael Watson]

Attached pictures show my problem.
Its a 10 inch figured walnut bowl. Moisture was down to slightly under 10%.
As I was making one of the last cuts near the top of the bowl, I heard a large "crack".
Stopped lathe and saw 2 cracks on opposite sides. Although there's lots of meandering grain, I think the cracks are in the end grain.
I had the top 1 1/2 inches down to 3/8ths of an inch. Bottom of bowl is still about 1 inch thick.
I've had this happen before in walnut, but never to this extent.
Cracking happened just after I had sharpened my 1/2 inch Thompson bowl gouge, so it wasn't a dull or overly hot tool.
Wasn't pushing too hard, just letting the gouge do its work.

any and all suggestions are appreciated.
MikeIMG_0413 (2).jpgIMG_0411 (2).jpgIMG_0412 (2).jpg

[John Keeton]

It would appear that you have left more of the pith area than is advisable.

[Fred Perreault]

It's happened to me more than once, and I suppose that it will happen again. Unless it is a commissioned work, I chalk it up to experience, and a chance to be creative. It's cracked, and we can't change that, but I have used CA glue and some kind of coloring such as fine sawdust, coffee or such, and glued it back together. It would then be something that we would use in our house (fruit bowl, etc.), or a friend or family member's home that appreciate the gift for what it is...... a repaired bowl. I even make the note "repaired" on the bottom when I sign it and identify the wood specie. It is sad, but there is something worth saving as best you can, I believe.

[Arlin Eastman]

Mike
All I can think of is the bowl was getting hot. I had that happen a few times when sanding.
Arlin

[Michael Watson]

John -
actually the pith was at least 3 inches "above" the top of the bowl.

[Prashun Patel]

How green was the wood?

It's always funny to me that people see cracks as defects. I think they're as natural as the grain, and it's something to be celebrated and highlighted, not shoved into a closet and not spoken of. Love the wood for what it is and what it does. That crack is a celebration of how wood moves as it dries and releases tension.

[Richard Coers]

I'd say the crack was probably already there and it opened up as the wood was exposed to the air. Close to the end of the log? You may have had a resonance while turning the thinner rim and that started the crack. I would not try to glue that one back together. Looks like firewood to me. Sorry!

[Harry Robinette]

I don't understand the top being 3/8 and the bottom 1 inch,I think your just for trouble to me. Any movement or pressure would have no were to go.If your cutting this way to make the wall thin I never go any more then one inch at a time and have only 1/2" to 5/8" thick walls to start. Then cut the top edge thinner and cut some from the wall.
Like I always say It's the way I do it.

[Thomas Canfield]

It looks like the bottom section has not been trued up, even though still thick. That produces some stress that could add to problem. Also the cuts done turning down to thin wall look rough at the step area like tool previously may have been dull, tearing out, and a lot of pressure applied. I agree with turning inside down in steps, but only after truing up the majority if not all of the inside. It almost looks like there is some tear out close to the rim which could be from earlier tear out not cleaning up. A sharper tool for all the turning might be helpful.

[Michael Watson]

Walnut has been drying for several years

[Robert Edington]

I've had this happen to me especially on cored (nested) walnut bowls. First I stabilize the crack with CA. Then what I do is get a piece of 1/4" graph paper and cut a strip wide enough to cover the entire length and width of the crack. Then I tape the graph paper over the crack. I take a very sharp awl type tool and make indentations in the wood at intersections in the graph paper. I do this the entire length of the crack. Then I drill through the bowl at every indentation. Then I take bare copper wire and lace across the crack in a decorative fashion and then tie off the copper wire in a neat manner.
I looked on the internet for lacing patterns and found there are many to choose from. People really like it. It looks like it was planned rather than fixed. Different gage wire will give a different effect. The graph paper gives you an evenly spaced grid for the holes.
On your bowl (if you have a plug cutter) you could cut a walnut plug and then drill the crack at the bottom and put the plug in the hole as a stabilizer and still finish turning it and then stitch it.
Or do something else.
RP in Brenham Texas

[Michael Watson]

Already made it into one of the most expensive jam chucks I have!

[Michael Watson]

Thanks for the comments.
Next time I'll try to keep the side walls and bottom more the same thickness, at least till final thinning is done.
Comment about dull tool may also be on target. I had just sharpened it prior to the crack, because it was awfully dull.

[Dennis Ford]

Don't give up because of a failure! If every piece came out perfect, this hobby would be boring. I suspect there was a lot of internal stress in this blank. How did you get it down to 10% moisture? Is it possible that the interior had a higher moisture content?

[Lee Koepke]

I've had this happen to me especially on cored (nested) walnut bowls. First I stabilize the crack with CA. Then what I do is get a piece of 1/4" graph paper and cut a strip wide enough to cover the entire length and width of the crack. Then I tape the graph paper over the crack. I take a very sharp awl type tool and make indentations in the wood at intersections in the graph paper. I do this the entire length of the crack. Then I drill through the bowl at every indentation. Then I take bare copper wire and lace across the crack in a decorative fashion and then tie off the copper wire in a neat manner.
I looked on the internet for lacing patterns and found there are many to choose from. People really like it. It looks like it was planned rather than fixed. Different gage wire will give a different effect. The graph paper gives you an evenly spaced grid for the holes.
On your bowl (if you have a plug cutter) you could cut a walnut plug and then drill the crack at the bottom and put the plug in the hole as a stabilizer and still finish turning it and then stitch it.
Or do something else.
RP in Brenham Texas

I have seen that done before, but never bothered to ask HOW. Thanks for sharing that.
Walnut can hide its internal cracks well, and drilling a plug is something else I hadnt thought of to keep the crack from propagating.